The present invention relates to a method of manufacturing phenol by a single stage direct oxidation of benzene.
A cumene process is widely used for manufacturing phenol. In the cumene process, phenol is obtained from the starting material benzene by the steps (I) to (III) given below:
(I) Cumene is produced by the reaction between benzene and propylene in the presence of an acid catalyst.
(II) Cumene hydroperoxide is produced by the reaction between cumene and oxygen.
(III) Cumene hydroperoxide is decomposed in the presence of an acid catalyst into phenol and acetone.
However, the cumene process, which involves three process steps, is not economical. Also, the phenol manufacture is dependent on the market price of acetone obtained as a by-product in the cumene process.
Under the circumstances, the present inventor has conducted an extensive research on the method to obtain phenol by direct oxidation of benzene in the presence of a Cu-supported catalyst. However, the conventional method is not satisfactory in the phenol yield and leaves room for further improvement in the phenol manufacturing cost.
An object of the present invention is to provide a method of manufacturing phenol by direct oxidation of benzene.
According to a first aspect of the present invention, there is provided a method of manufacturing phenol, comprising the steps of placing benzene, a reducing agent and a vanadium-supported alumina catalyst in an aqueous solution of acetic acid used as a solvent, and directly oxidizing benzene under an oxygen gas atmosphere to produce phenol.
According to a second aspect of the present invention, there is provided a method of manufacturing phenol, comprising the steps of placing benzene and a zinc-vanadium-supported alumina catalyst in an aqueous solution of acetic acid used as a solvent, and directly oxidizing benzene under an oxygen gas atmosphere to produce phenol.
Further, according to a third aspect of the present invention, there is provided a method of manufacturing phenol, comprising the steps of supplying benzene and an oxidant of N2O into a circulating reactor loaded with a copper-supported zeolite catalyst, and directly oxidizing benzene to produce phenol.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.